001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.compress.harmony.unpack200.bytecode.forms; 018 019import org.apache.commons.compress.harmony.unpack200.bytecode.ByteCode; 020import org.apache.commons.compress.harmony.unpack200.bytecode.CodeAttribute; 021import org.apache.commons.compress.harmony.unpack200.bytecode.OperandManager; 022 023/** 024 * This class implements the byte code form for those bytecodes which have label references (and only label references). 025 */ 026public class LabelForm extends ByteCodeForm { 027 028 protected boolean widened; 029 030 public LabelForm(final int opcode, final String name, final int[] rewrite) { 031 super(opcode, name, rewrite); 032 } 033 034 public LabelForm(final int opcode, final String name, final int[] rewrite, final boolean widened) { 035 this(opcode, name, rewrite); 036 this.widened = widened; 037 } 038 039 /* 040 * (non-Javadoc) 041 * 042 * @see 043 * org.apache.commons.compress.harmony.unpack200.bytecode.forms.ByteCodeForm#fixUpByteCodeTarget(org.apache.commons. 044 * compress.harmony.unpack200.bytecode.ByteCode, 045 * org.apache.commons.compress.harmony.unpack200.bytecode.CodeAttribute) 046 */ 047 @Override 048 public void fixUpByteCodeTargets(final ByteCode byteCode, final CodeAttribute codeAttribute) { 049 // LabelForms need to fix up the target of label operations 050 final int originalTarget = byteCode.getByteCodeTargets()[0]; 051 final int sourceIndex = byteCode.getByteCodeIndex(); 052 final int absoluteInstructionTargetIndex = sourceIndex + originalTarget; 053 final int targetValue = ((Integer) codeAttribute.byteCodeOffsets.get(absoluteInstructionTargetIndex)) 054 .intValue(); 055 final int sourceValue = ((Integer) codeAttribute.byteCodeOffsets.get(sourceIndex)).intValue(); 056 // The operand is the difference between the source instruction 057 // and the destination instruction. 058 byteCode.setOperandSigned2Bytes(targetValue - sourceValue, 0); 059 if (widened) { 060 byteCode.setNestedPositions(new int[][] {{0, 4}}); 061 } else { 062 byteCode.setNestedPositions(new int[][] {{0, 2}}); 063 } 064 } 065 066 /* 067 * (non-Javadoc) 068 * 069 * @see 070 * org.apache.commons.compress.harmony.unpack200.bytecode.forms.ByteCodeForm#setByteCodeOperands(org.apache.commons. 071 * compress.harmony.unpack200.bytecode.ByteCode, 072 * org.apache.commons.compress.harmony.unpack200.bytecode.OperandTable, 073 * org.apache.commons.compress.harmony.unpack200.SegmentConstantPool) 074 */ 075 @Override 076 public void setByteCodeOperands(final ByteCode byteCode, final OperandManager operandManager, 077 final int codeLength) { 078 byteCode.setByteCodeTargets(new int[] {operandManager.nextLabel()}); 079 // The byte code operands actually get set later - 080 // once we have all the bytecodes - in fixUpByteCodeTarget(). 081 return; 082 } 083}